Glaucoma is an eye condition that can cause damage to the optic nerve. This nerve is essential for your eye health. If it becomes damaged, it can cause permanent vision loss and, in some cases, it may even lead to blindness.

Glaucoma is typically caused by high pressure inside your eyes. However, diabetes can also be a risk factor for glaucoma.

In this article, we’ll take a closer look at the link between diabetes and glaucoma, and the steps you can take to help protect your eye health.

Your eyes continuously produce a clear fluid known as the aqueous humor that fills the inside of your eye. New fluid constantly replaces the older fluid, which leaves your eye through a meshwork drainage field and channels.

If something obstructs this drainage mechanism, the natural pressure inside your eye — known as your intraocular pressure (IOP) — can increase. If your IOP increases too much, it can damage the fibers of your optic nerve.

As damage to this nerve progresses, you may begin losing sight in your eye, especially in your peripheral vision.

There are two primary types of glaucoma: open-angle and closed-angle.

  • Open-angle glaucoma is the most common kind. With this type of glaucoma, the pressure builds slowly and loss of vision happens gradually.
  • Closed-angle glaucoma accounts for around 10 percent of cases. The symptoms happen very suddenly, and it’s a more dangerous type of glaucoma that needs urgent medical attention.

According to a 2017 study, diabetes may raise your risk of open-angle glaucoma by approximately 36 percent. Closed-angle glaucoma does not seem to have a known connection with diabetes.

Diabetic retinopathy, which is a complication of diabetes and the most common form of diabetic eye disease, can increase your risk of glaucoma.

Diabetic retinopathy usually affects people who have had diabetes for a long time. The risk of this condition increases with:

With diabetic retinopathy, changes in your glucose levels can cause the blood vessels in your retina to weaken and become damaged. This can eventually lead to glaucoma.

The leading theory is that when the blood vessels in your retina become damaged, it can cause abnormal blood vessels to grow in your eye, known as neurovascular glaucoma. These blood vessels can block your eye’s natural drainage system. When this happens, it can cause your eye pressure to increase, which can lead to glaucoma.

Another theory as to how diabetic retinopathy increases the risk of glaucoma points to high blood sugar as the direct cause. According to this theory, high blood sugar can cause an increase in a specific glycoprotein, called fibronectin, to form in your eye. Having more fibronectin in your eye may block your eye’s natural drainage system, which can lead to glaucoma.

Glaucoma typically doesn’t have any symptoms, especially in the early stages. Because glaucoma causes gradual changes in your vision, you might not notice any symptoms until it’s more advanced. If left untreated, glaucoma can lead to severe vision loss or blindness.

If you do have symptoms of glaucoma, the symptoms will vary depending on the type of glaucoma and how advanced the disease is.

Open-angle glaucoma

Symptoms may include:

Closed-angle glaucoma

This type of glaucoma is a medical emergency and requires immediate treatment. Symptoms may include:

Neurovascular glaucoma

Symptoms may include:

  • eye pain
  • eye redness
  • vision loss

Because glaucoma often doesn’t have symptoms in the early stages, it’s important to get regular eye exams. This is especially important if you have any risk factors, including diabetes.

According to the Centers for Disease Control and Prevention (CDC), people with diabetes should get a dilated eye exam every year. Having your eyes dilated can help your eye doctor to more easily check for optic nerve damage or other issues.

During your eye exam, your doctor will also measure the pressure in your eyes. Depending on your risk, you might need other tests, such as checking for areas of vision loss, measuring the thickness of your cornea, and looking at the angle at which your eye drains fluid.

If you receive a glaucoma diagnosis, prescription eye drops are usually the first treatment option.

If the eye drops don’t help reduce the pressure buildup in your eye, your doctor may suggest medication or surgery.

Surgery options for glaucoma include:

  • laser therapy to open clogged channels in your eye
  • the insertion of drainage tubes or stents to help drain the fluid in your eye
  • removal of the damaged parts of your eye drainage system

Depending on your diabetes management and other risk factors, you may be at a higher risk of developing other eye issues, too.

Short-term spikes in your blood sugar, which can happen when you’re changing your treatment, can cause swelling or high fluid levels in your eye. This can cause temporary blurry vision. This will likely go away once your blood sugar stabilizes.

Long-term elevated blood sugar levels can damage the blood vessels in your eye and lead to conditions, such as:

  • Diabetic macular edema. This condition causes swelling in the macula, an area in the center of your retina. It can cause partial vision loss or blindness.
  • Cataracts. People with diabetes may develop cataracts at an earlier average age than people without diabetes. Experts think this may be because high blood sugar levels can cause deposits to build up on the lenses of the eyes.

If you have diabetes, it’s very important to protect your eye health, as well as your general health. To lower your risk of glaucoma and other eye issues with diabetes, be sure to:

  • carefully follow your diabetes care plan to keep your blood sugar levels within a safe range
  • have an eye exam with dilation every year
  • avoid smoking
  • get regular exercise
  • use any prescribed eye drops or medication for high eye pressure exactly as your doctor tells you to

Diabetes can increase your risk of several eye diseases, including glaucoma.

Diabetic retinopathy, which is a complication of diabetes, can result in damage to the blood vessels in your retina. This can cause abnormal blood vessels to grow in your eye, which can block your eye’s natural drainage system and eventually lead to glaucoma.

Because glaucoma often has no symptoms, especially in the early stages, it’s important to get annual eye exams if you have diabetes.